Northeast Iowa - Southwest Wisconsin Significant Flooding

Last Updated: 5/26/04

Several days of heavy rain, including at least 5 individual thunderstorm complexes, tracked across northeast Iowa and southwest Wisconsin from Friday May 21st through Sunday May 23rd. Record river flooding and widespread flash flooding was reported in the region after some areas received 8-10 inches of rain. The bulk of the heavy rain fell Friday night and again Saturday night.

Record river levels were set on the Volga and Turkey River in northeast Iowa. The crest reading for the Turkey River at Garber, IA topped out at 33.14 ft, which is about 2 1/2 feet over the previous record set back in 1999. Flood stage at Garber is 17 feet.

Timetable of information released:

  • Thu. May 20th - Hydrologic Outlook issued (4 a.m.) warning of heavy rain and possible flooding over the weekend.
  • Fri. May 21st - Flood Watch issued (4 a.m.) for Friday night stating that flooding was expected.
  • Fri. May 21st - Flash Flood Warnings started around 7 p.m. for northeast Iowa and southwest Wisconsin.
  • A total of 39 Flash Flood Warnings were issued Friday and Saturday nights, May 21-22.
  • A total of 20 Severe Thunderstorm Warnings were issued over the 3 day period.
  • River Flood Warnings began on Friday and increased by Saturday morning, May 22nd.

These photos of river flooding and damage were taken by NWS La Crosse on May 23, 2004, unless otherwise noted.

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Turkey River at the Keystone Bridge in Elkader, IA. Flood damage at Elkader, IA. Turkey River at Millville, IA along Highway 52.
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Erosion damage to county road near Mederville, IA. Volga River at Elkport, IA. Clayton County Sheriff car stranded by high water near Volga, IA.
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Receded flood waters that were 4-5 feet deep in central Clayton County, IA. Eroded drive along Roberts Creek near Elkader, IA. Sand bagging efforts in Spillville, IA.
Hydrology Details and Graphs
Cedar River at Charles City Crest: 16.5 ft  Sun 5/23 230am
Upper Iowa River at Dorchester Crest:15.6 ft Sat 5/22 4pm and
15.6 ft Sun 5/23 10pm
Turkey River at Garber Crest*: 33.1 ft Sun 5/23 1pm
Turkey River at Elkader (EKDI4) Crest: 25.6 ft Sun 5/23 7am
Turkey River at El Dorado Crest: 19.6 ft Sun 130pm
  - Volga River at Littleport Crest: 22.0 ft Sun 5/23 830am
* indicates Record Flood and estimated stage Help: Geographic Information
on these rivers.
Rainfall Totals
radar rainfall estimation radar rainfall estimation radar rainfall estimation
Radar Estimates through Friday at 7 pm (May 21) Radar Estimates through Saturday at 5 pm (May 22) Radar Estimates from Saturday at 7 pm (May 22) to Sunday at 7 pm (May 23)
3-day Measured Rainfall Totals (Friday May 21-Monday May 24) Graphic
More Weather Information
A persistent frontal boundary was located very near to I-80 across central Iowa for the period. Although the fronts exact location changed by tens of miles north and south, Gulf of Mexico moisture was being transported northward into the front. As this moisture encountered the front it was lifted over a colder, more dense air mass over northern Iowa and southwest Wisconsin. This lifting produced thunderstorm initiation releasing the potential energy carried from the Gulf resulting in the production of large hail and heavy rainfall.

Since the frontal boundary extended the length of Iowa east-west, thunderstorms erupted each day and night over most of northern Iowa. Upper level winds from the west then carried this 'line' of thunderstorms east. Much like a train rolls down the rails, each thunderstorm acted like a train-car and ran over northeast Iowa and southwest Wisconsin. While it seems like one long thunderstorm affected this area, it was actually storm after storm after storm...for hours on end. This saturated once dry soils and by Saturday night, much of the rainfall ran off into creeks and rivers. 

radar image radar image
Radar image from 7 pm Friday showing the front, and two distinct thunderstorm complexes. Northeast Iowa about to be affected. Radar image from 1 am Saturday morning showing the thunderstorms continue to affect northeast Iowa and southwest Wisconsin.
Why no severe winds or tornadoes? With such a cold, dense, and stable air mass near the surface, downward moving air  produced in the thunderstorm above the surface has trouble reaching the surface through this dense air.  Thus, heavy rain and hail are mainly observed with this weather pattern.
Shea/Baumgardt/Boyne/Swerman/Schreck....7:54 a.m. 5/26/2004 is the U.S. government's official web portal to all federal, state and local government web resources and services.